Spark timing indicator



' June 22, 1943.

J. S. BUCKWALTER SPARK TIMING INDICATOR Filed on. 20, 1941 ATTORNEYS Patented June 22, 1943 UNITED STATES PATENT OFFICE SPARK TIMING INDICATOR Jacob S. Buckwalter, Philadelphia, Pa. Application October 20, 1941, Serial No. 415,846 I 1 Claim. (01. 33-181) My invention relates to spark timing indicators and has for an object thereof to provide an indicating device which will enable the determination of the fire timing of the pistons of an internal combustion engine. 1

Another object of the invention is the provision of an indicating device of the aforesaid character which provides simple and improved means wherein the spark timing of an ignition system may be adjusted.

A further object of the invention is the provision of a spark timing indicator which is relatively simple and inexpensive in construction and which is efiicient and reliable in operation.

Other objects and advantages of the invention will become apparent as the description progresses.

In the accompanying drawing forming a part of this specification and in which like numerals are employed to designate corresponding parts throughout:

Figure 1 is a side elevational view of the indicating device,

Figure 2 is a vertical sectional view'taken on line 2--2 of Figure 1 and showing the device operatively connected with the cylinder head of an internal combustion engine, and

Figure 3 is a bottom plan view of the device partly in section. 7

Referring to the drawing, wherein is illustrated a preferred example of the invention, 5 designates a tubular housing having a bottom reduced and threaded shank portion 6 which is designed to be screwed into the threaded spark plug opening I in the head of an internal combustion engine. The upper portion of the housing 5 is formed interiorly with a shoulder 9 for seating thereon the enlarged shoulder portion IU of a sleeve H fitted within the housing. Above the shoulder I downwardly to contact with the top face of a piston l6 mounted to reciprocate within a cylinder ll of an internal combustion engine, and to which the head 8 is fastened. At a medial position the rod [3 is provided with a longitudinally At the upper end of the sleeve II is provided 7 a web Zil to which is rigidly connected the lower reduced end of a triangular-shaped upstanding indicator plate 2!. To a pivot connection on the upper end portion of the sleeve H is connected an elongated tapered indicator hand 22 formed with a hub 23 at the bottom mounted on the pivot and formed with a shoulder 24 designed to engage the upper end of an ajutment 25 provided on the upper end of the rod l3, as shown to advantage at Figure 2.

On the front face of the plate 2| is secured one end of a coiled spring 25 mounted so that the opposite end extension slidably contacts with the I indicator 22 so as to yieldingly urge the shoulder 24 against the ajutment 25. On the upper portion of the plate is secured an arcuate approximately U-shaped guide bracket 21 which serves to guide and limit the swinging movement of the indicator hand, On the upper marginal portion of the plate are provided a plurality of scale graduations 28 arranged in coactin-g relation with the upper free end of the indicator. The scale 28 has a graduation 29 designated by the figure 0 indicative of the extreme right hand movement of the indicator as viewed at Figure 2.

In the use of the device, the usual spark plug, indicated at 30, is removed from an opening in the engine head and placed in electrical contacting position on top of the head. The improved indicating device is then mounted in place of the spark plug as illustrated in the drawing. By

- slowly turning the engine shaft, preferably with the fuel supply cut olf and the ignition switch closed, the piston is brought to its topmost position wherein it contacts the arm Hi to elevate the rod l3 and swing the pointer to a position in reg istration with the zero marking on the scale, thus affording a proper setting of the device. As the piston rises after effecting such operation, against the force of the coil spring 26, it swings the arm l4 about the friction pivot connection with the rod i3 and thereby establishes the full elevation of the piston with a zero indication on the dial. Thereafter the piston may be moved to ascertain the time of sparking with relation to the topmost piston position, the dial designating such relation in degrees of the piston movement. If the engine has been faulty in operation and this timing relation is found to be defective it becomes readily apparent that adjustment should be made and the new adjustment verified by the use of the indicating device.

Without further elaboration, the foregoing will so fully explain the invention that others may, by applying current knowledge, readily adapt the same for use under various conditions of service. Moreover, it is not indispensable that all the features of the invention be used conjointly since they may be employed advantageously in various combinations and sub-combinations.

What is claimed is:

In a spark timing indicator for internal combustion engines, a tubular housing adapted to be fitted into the spark plug opening of an internal combustion engine, a plunger rod slidably fitted in the said housing and projecting inwardly thereof, means for limiting the axial sliding movement of the plunger rod, an arm having frictional pivot connection with the inner end of the plunger and extending angularly therefrom to engage the piston of an engine, an indicator plate attached to and extending outwardly from the housing, a pointer pivotally mounted adjacent the inner end of the plate for swinging movement along a face of the plate, the said pointer having a shoulder at its inner end, a projection on the outer end of the plunger engageable with the shoulder on the pointer to effect operative movement of the latter upon axial movement of the plunger, a spring fixed to the indicator plate and pressing against the pointer so as to yieldingly urge the latter against movement by the plunger, and a bracket secured on the indicator plate for limiting the swinging movement of the pointer.

JACOB S. BUCKWALTER. 

